Ben Riley-Smith is a Telegraph political reporter covering the Scottish independence referendum. Get in touch via @benrileysmith or ben.riley-smith@telegraph.co.uk

Scottish independence: Who really benefits when big business speaks out?

Another day, another big business intervention. This time it's the head of Shell, the Anglo-Dutch oil giant, who has decided to speak out against Scottish independence.

“We’d like to see Scotland remain part of the United Kingdom," said Ben van Beurden, Shell's chief executive, last night in comments that are running high on today's news bulletins. The UK, he added, offers "continuity and stability".

Mr Van Beurden's not alone. In fact, over the last few week there has been a constant drip, drip, drip of FTSE 100 companies making unnerving remarks about the uncertainty created by Scottish independence.

The list of companies to have warned about the impact of leaving the UK now includes: BP, Shell, Standard Life, RBS, Lloyds Banking Group, Sainsbury's, Asda, plus a whole host of Scottish companies and British trade bodies. That list is only going to keep growing as annual report season continues.

For Better Together, the campaign fighting to keep the UK as one, this is an unmitigated triumph for two reasons. Firstly, they believe that uncertainty is the biggest deterrent to voters who might tick Yes come September 18. Secondly, the economy is the number one issue for the electorate. Surely if Britain's leading companies speak out about the uncertainty of independence, this can only benefit the No camp?

Not necessarily. In between the damning headlines – "referendum hurting investment"; "banks could flee after independence" – there is a counter-argument being voiced in some quarters. It goes roughly like this: when loaded executives tell me not to vote Yes because it hurts their profits, I'm more likely to do just that.

Matt Qvortrup, a former adviser to the US State Department and author of A Comparative Study of Referendums, put it most succinctly a few weeks ago in The Sunday Times.

Voters do not study the details of the proposal. They base their decisions on statements by people they trust. And voters do not trust rich businessmen. The captains of industry may be admired for their skills and ingenuity, but they do not share the plight of ordinary people; they do not worry about mortgages and the like …
You do not win a referendum with statements by the rich and powerful. To succeed at the ballot box you must convey the impression you represent the average voter — that your side will improve the lives of the ordinary citizens.

You can go too far with this line. Early indications suggest that an intervention by George Osborne – who isn't topping any popularity charts north of the border – ruling out sharing the pound seems to have worked. The latest Ipsos Mori poll says 34 per cent of undecided voters are more likely to reject independence since the announcement; that's double the 16 per cent more likely to vote Yes.

Plus, as Better Together would argue, genuine captains of industry who have made good all by themselves hold an admiration in the minds of the electorate that few other professions can rival.

But even so, there is some doubt about which way this will play. John Curtice, professor of politics at Strathclyde University and pre-eminent Scottish poll-watcher, says big business interventions aren't a guaranteed win for Unionists.

"In general, what is undoubtedly true is the willingness of people to believe a message does depend on the credibility of the source," he said.

"You have to remember what's in the back of all our minds was business wasn't too keen on devolution. It was on the wrong side of the argument in 1997, so it doesn't always work."

The Nationalists have been having particular fun with this one too. When Standard Life came out harder than expected against independence in its annual report last week, a newspaper cutting was dug out showing they made a near identical warning in 1992. "Finance chiefs warn of home rule dangers", the headline ran. Almost 75 per cent went on to back devolution when a referendum eventually came round in 1997.

None of that guarantees a repeat this year, but they are omens well worth acknowledging. As Prof Curtice says, tone is everything. "If a company says 'we think this is a bad idea because it is going to cut our profits', people might go 'so what'," he says. "If on the other hand they say … something that is reasonable and directed at the welfare of the country as a whole, then maybe it will have some influence."

Above all, he says, big business must avoid the "fear and loathing end of the argument" if their message is to be effective. The question is, how much fear and loathing will the executives elicit themselves from the electorate? A hell of a lot is riding on that answer, for both sides.